The arsonist Jerry "The Fire Ant" McMillan has been arrested by Francis Grimes for violating his parole. Mark Lilly succeeds in persuading Twayne Boneraper to release Jerry to counseling in his class since Twayne is happily in love with his new girlfriend Emily.
After much trouble, Mark has finally made Jerry open up himself and reveals that he was an orphan with an alcoholic foster father. Jerry even hands over all his arson tools hidden across the city.
However, Randall Skeffington comes to the meeting in the Department of Integration and exposes Jerry actually used to have a father who was a Lutheran minister. Jerry escapes by going inside Twayne's body through his nose.
Leonard Powers casts a shrinking spell on Mark, Grimes and himself which will last 8 hours. Together they enter Twayne's body on a motor vehicle. Randall and Callie Maggotbone go out to investigate Jerry's background.
Leonard tells Mark and Grimes that the 8-hour spell duration equals to 8 "Twayne days" inside his body. They are soon caught by some stomach bacteria and brought to a village. Leonard casts a translation spell to allow communication. There they meet the village chief and his daughter Princess Chlamydia. The chief calls Mark by the name "Lesbian Hair".
Grimes and the princess fall in love and get married quickly. On the wedding, Jerry appears and is enraged to discover the three men have followed him. He sets the bacterial village on fire and kills the chief.
The three men once again pursue Jerry all over inside Twayne's body, giving Twayne much pain.
Callie and Randall find out from Jerry's old cellmate that Jerry was writing to somebody while in jail. The cellmate gives them a letter left behind by Jerry. They find out the letter was written for a stripper named Porsha working at The Boob Factory. They go to The Boob Factory and discover who Porsha really is. Callie calls Mark on the cell and tells him their findings.
Mark discovers Jerry near Twayne's brain and finds him at Twayne's eye. He points out that Porsha is actually Twayne's new girlfriend Emily and Jerry is risking his life to see her again. Jerry tells Mark that he had a relationship with Porsha after leaving jail. But Porsha was not willing to give up her job as a stripper so he left her. He was angry to discover she changed her way for Twayne.
Mark helps Jerry to see that Porsha is not actually in love with Twayne but ripping him off. As Jerry decides to change his ways, Grimes appears and kills him with a bone spear. They bury Jerry in Twayne's sinus cavity.
They return to the bacterial village. Princess Chlamydia awards Mark with the "Crown of Heroes" which is made out of Twayne's dried sperm cells. Leonard urges Mark to take a bite to avoid offending her. Then they begin to grow and race quickly out of Twayne's butt in front of Porsha. Porsha leaves in disgust and stole a statue from Twayne.
Princess Chlamydia is still able to talk to Grimes with Mark's cellphone which has been left behind in Twayne's body. Porsha is seen sent away to the Stripper Prison at the end.
- As each demon's inside is unique, apart from some strange living organisms, Twayne even has a sun inside his body.
- A running gag of the episode is Randall dress and acting as Horatio Cane from the CSI: Miami series.